Device for detecting moisture in a fluid



Feb. 12, 1963 c. E. OHLHEISER 3,0

DEVICE F OR DETECTING MOISTURE IN A FLUID Filed Nov. 9. 1959 A rroems Y United States PatentQflflce 3,d77,l Patented Feb. 12, 1953 3,977,105 DEVKIE FOR DETECTING MOISTURE Bi A FLUTE Carlton E. Ohlheiser, Silver Spring, Md, assignor to American instrument (Zompany, 1218-, dilver Spring, Md. Filed Nov. 9, 1959, der. No. 8571,76? 7 Claims. (Cl. 73-53) This invention relates to moisture controlling systems, and more particularly to means for controlling the amount of moisture in a fluid employed in the processing of material.

A main object of the invention is to provide an improved device for detecting the amount of moisture in a fluid, said device involving no moving parts, being compact in size, and being non-clogging.

A further object of the invention is to provide an improved self-cleaning electrical moisture detecting unit for use in a system employing a circulating fluid containing moisture, said unit being rugged in construction,

being compact in size, providing accurate indications of the amount of moisture in said circulating fluid, and serving as a means for continuously regulating said amount of moisture so as to maintain it within desired limits.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

FIGURE 1 is a front elevational view, partly in vertical cross-section, of a controller employing a moisture detecting unit according to the present invention with its front cover removed.

FIGURE 2 is an enlarged vertical cross-sectional view taken through the electrical moisture sensing member of the moisture detecting unit of FIGURE 1.

Referring to the drawings, a moisture sensing member 27 is mounted Within a first heat exchange coil 25 so that said moisture sensing member is maintained substantially at the same temperature as the coil 25. Thus, the heat exchange coils 25 and 26, and the moisture sensing member 27, are enclosed in the housing of a moisture controller 19, which also contains the electrical portion of the moisture detecting unit, shown at 29, the electrical device 29 including a heating resistance which is suitably energized to maintain the interior of'the housing of the moisture controller 1% at a constant temperature. Heat from the electrical device 29 stabilizes the temperature of the heat exchange coils 25 and 26 so that the temperature of the fluid admitted into the moisture sensing member 27 is maintained substantially constant at all times during the operation of the apparatus.

The electrical device 29 is generally similar to the device described in applicants copending application, Serial No. 516,462, filed June 20, 1955, now Patent No. 2,943,245, entitled Humidity Control Device.

As shown in FTGURES 1 and 2, the moisture sensing member 27 comprises an annular top cap member 63 which is threadedly secured on the top portion of an externally threaded nipple member 64 having a relatively rough interior Wall surface 65. Threaded on the lower portion of nipple member 64 opposing top cap member 63 is an annular bottom cap member 86, to the bottom of which is connected the discharge conduit 28 leading to the cleaning tank 11.

Rigidly secured in the top capmember 63 is the depending annular skirt member 66 which extends through and below the nipple member 64, being spaced relatively closely to the inside surface 65 of the nipple member 64 and defining therebetween an annular space 63 which leads to the bottom cap member 36.

Skirt member 66 is formed at its intermediate internal portion with an inwardly projecting annular flange 70. The humidity sensing element 6%) is disposed in inverted position in the skirt member 66, the sensing element being provided with a base 71 which is formed with an annular flange 72 supportingly engaged on the flange 7i}. An annular clamping ring 73 surrounds the upper portion or" base 71 and is threadedly engaged in the upper portion of skirt member 66, exerting clamping force on the flange 72 to rigidly secure base 71 in the skirt member 66 in the position illustrated in FIGURE 2. The sensing element 66, which is of the pronged type, is thus supported in a depending position axially in the skirt member 66 with its humidity-sensitive surface spaced from and exposed to the internal surface of the skirt member 66. As shown, the skirt member extends sufficiently below the sensing element to protect same against direct contact with liquid.

The top cap member 63 is provided with an inclined fluid inlet fitting 74 discharging into the upper annular space 75 in cap member 63 leading to the annular space 68. The top end of heat exchange coil 26 is connected to the fitting 74- so that fluid from coil 26 is discharged into the spaces 75 and 68 at substantial pressure and is forced through the relatively restricted annular space defined between skirt 66 and surface 65. The fluid emerges below said annular space in the form of a rapidly moving cylindrical tube of the liquid, freeing to the inner space molecules of water vapor at a vapor pressure proportional to the amount of water contained in the fluid and causing a measurable relative humidity to exist within the inner periphery of the cylinder. Since sensing element 69 is exposed to the water vapor, said element will respond to vary its resistance in accordance with the amount of moisture present in the inverse manner above described.

A sight glass unit 76 is provided in conduit 28 subjacent the controller l to provide a visual indication of the flow through the coils 25, 26 and the member 27.

The humidity-sensing element 60 is electrically connected to the electrical device 29 by a cable 77 provided with a female plug connector 78 engaged on the prongs 79 of the sensing element.

Suflicient clearance exists between the roughened inside surface 65 of nipple member 64 and the skirt member 66 to allow the fluid to discharge through the annular nozzle thus defined with considerable velocity, While providing a self-clearing action which prevents the nozzle from becoming clogged or obstructed. The rapid movement of the fluid through the nozzle prevents sediment or other fluid-carried material from being deposited on the surfaces of the nozzle or on the surfaces adjacent thereto. Surface 65 is preferably roughened, although the device will operate if surface 65 is smooth instead of being roughened. The liquid is admitted to the nozzle under substantial pressure, for example, under a pressure of approximately 40 pounds per square inch.

While a specific embodiment of a moisture controlling system has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore is it intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. A moisture detector comprising a chamber provided with fluid inlet means at one end portion thereof and fluid outlet means at the other end portion thereof, said chamber including a generally cylindrical intermediate portion, a skirt member secured. substantially axially in said chamber and depending into said intermediate portion, said skirt member being spaced from the inside surface of said intermediate portion and defining an annular restriction of substantial axial length between said skirt member and the inside surface of said intermediate portion, said chamber having an enlarged space communicating with the end of said annular restriction for .free molecules of water vapor released from liquid'discharged through said annular restriction, and a humidity-sensing element secured in said skirt member and exposed to said enlarged space.

2. Amoisture detector comprising a chamber provided with fluid inlet means at one end portion thereof and fluid outlet means at the other end portion thereof, said chamber including a substantially upright generally cylindrical intermediate portion, a skirt member secured substantially axially in said chamber and depending into saidintermediate portion, said skirt member being spaced from the inside surface of said intermediate portion and defining an annular restriction of substantial axial length between said skirt member and the inside surface of said intermediate portion, said chamber having an enlarge'd space communicating with the end of said an- 'nular restriction for free molecules of water vapor released from liquid discharged through said annular restn'ction, and a humidity-sensing element secured substantially axially in said skirt member and exposed to "said enlarged space.

3. A moisture detector compri'sing'a chamber provided with fluid inlet means at *one end portion thereof and fluid outlet means at the other end portion thereof, said chamber including a substantially upright generally cylindrical intermediate portion, a skirt member secured substantially axially in said chamber and depending into said intermediate portion, said skirt member being spaced from the inside surface of said intermediate portion and defining an annular restriction of substantial axial length betweensaid skirt member and the inside surface of said intermediate portion, said chamber having an enlarged space communicating with the end ofsaid annular restriction 'for'free molecules of water vapor released from liquid discharged through said annular restriction, and a humidity-sensing element of the bifilar wound type secured substantially axially in said skirt member and exposed 'to said enlarged space.

'4. A moisture'detector of the character described comprising a chamber provided with fluid inlet means at its uppersportion and fluid outlet means'at its lower portion, said chamber having .a substantially cylindrical intermediate "internal wall spaced between said fluid inlet means and fluid outlet means, means in said chamber defining fa fluid admission space adjacent the upper portion of said internal wall and communicating with said fluid inlet means, housing means defining an annular restriction of substantial axial length between said fluid admission space and said internal wall, said chamber having an enlarged space communicating with the end of said annular restriction for free molecules of water vapor released from liquid discharged through said annular restriction, and a humidity-sensing element secured substantially axially in said housing means and exposed to said enlarged space.

5. A moisture detector of the character described comprising a chamber provided with fluid inlet means at its upper end and fluid outlet means at its lower end, said chamber including an intermediate passage, housing means in said intermediate passage defining externally thereof an annular restriction of substantial axial length in said intermediate passage, said housing means opening into the lower end of said chamber, and a humidity sensing element mounted in said'housing means and being exposed to said lower end of the chamber.

6. A moisture detector of the character described comprising a chamber provided with fluid inlet means at its upper portion and fluid outlet means at its lower portion, said chamber having a substantially cylindrical inwardly offset intermediate wall portion spaced between said fluid inlet means and fluid outlet means, whereby to define a fluid admission space at the upper portion of the chamber communicating with said fluid inlet means and an enlarged space at the lower portion of the chamber communicating with-said fluid outlet means, a depending housing element secured in the top portion of said chamber and openinginto said lower enlarged space, said housing element extending closely adjacent to said intermediate wall portion to define an annular restriction of substantial axial length between said .fluid admission space and said lower enlarged space, and a humidity sensing element secured substantially axially in said housing element and exposed to said lower enlarged space. 7 The structure-of claim 6, and wherein said depending housing element extends into said lower enlarged space.

References Cited in the file of this patent UNITED STATES PATENTS 2,654,067 Bruce Sept. 29, 1953 2,737,562 Thornton Mar. 6, 1956 2,762,218 Ohlheiser Sept. 11, 1956 2,913,893 .Mathews' Nov. 24, 9 2,915,701 -Broerman. Dec. 1, 1959 2,967,084 Reitz Jan. 3, .1961 2,973,010 Lyle Feb. 28,1961 

1. A MOISTURE DETECTOR COMPRISING A CHAMBER PROVIDED WITH FLUID INLET MEANS AT ONE END PORTION THEREOF AND FLUID OUTLET MEANS AT THE OTHER END PORTION THEREOF, SAID CHAMBER INCLUDING A GENERALLY CYLINDRICAL INTERMEDIATE PORTION, A SKIRT MEMBER SECURED SUBSTANTIALLY AXIALLY IN SAID CHAMBER AND DEPENDING INTO SAID INTERMEDIATE PORTION, SAID SKIRT MEMBER BEING SPACED FROM THE INSIDE SURFACE OF SAID INTERMEDIATE PORTION AND DEFINING AN ANNULAR RESTRICTION OF SUBSTANTIAL AXIAL LENGTH BETWEEN SAID SKIRT MEMBER AND THE INSIDE SURFACE OF SAID INTERMEDIATE PORTION, SAID CHAMBER HAVING AN ENLARGED SPACE COMMUNICATING WITH THE END OF SAID ANNULAR RESTRICTION FOR FREE MOLECULES OF WATER VAPOR RELEASED FROM LIQUID DISCHARGED THROUGH SAID ANNULAR RESTRICTION, AND A HUMIDITY-SENSING ELEMENT SECURED IN SAID SKIRT MEMBER AND EXPOSED TO SAID ENLARGED SPACE. 